Module domain 

Domain Layer Marker Traits

This module provides marker traits for enforcing domain-driven design boundaries at compile time. Types marked with these traits are guaranteed to be free of infrastructure dependencies (sqlx, sea_orm, http, axum, etc.).

Usage

Use the #[domain_model] attribute macro to mark domain types:

use modkit_macros::domain_model;

#[domain_model]
pub struct User {
    pub id: Uuid,
    pub email: String,
    pub created_at: DateTime<Utc>,
}

The macro will:

• Implement DomainModel for the type
• Validate at macro-expansion time that all fields are free of infrastructure types
• Generate clear error messages if forbidden types are detected

Enforcement

Domain services can use trait bounds to ensure they only work with domain types:

pub trait UserRepository: Send + Sync {
    type Model: DomainModel;

    async fn find(&self, id: Uuid) -> Result<Option<Self::Model>>;
}

Validation Strategy

The #[domain_model] macro performs validation by checking field type names against a list of forbidden patterns (e.g., sqlx::, http::, sea_orm::). This provides clear error messages at macro expansion time, similar to how #[api_dto] validates its arguments.

Additional enforcement is provided by Dylint lints:

• DE0301: Prohibits infrastructure imports in domain layer
• DE0308: Prohibits HTTP types in domain layer

Traits

DomainErrorMarker

Marker trait for domain errors.

DomainModel

Marker trait for domain models (business entities).